The former prime minister said it would be a ‘long process’ and have to be based on mutual agreement.
Former British prime minister Gordon Brown has said it is inevitable that Ireland will become united at some point in the future.
He added that it would be a “long process” and have to be based on mutual agreement.
Mr Brown, in an interview with the Guardian, said that Northern Ireland is in a potentially different position compared to the rest of the UK, giving Scotland as an example.
Asked about pressure for Scottish independence, Mr Brown said: “Scotland’s got to find a way of living in cooperation with other countries, and independence would not be the right way forward.
“We’re geographically, economically, socially, culturally linked to the rest of the United Kingdom, whether it’s Wales, England or parts of Ireland.”
Asked if the land border between Northern Ireland and the Republic meant uniting the two made sense, he said: “Yes. Well, of course, in the long term, Ireland will be united.”
He said the process would be long.
“People have got to come together and find a way of agreeing. Basically, that is the issue: whether people can actually agree.”
Mr Brown was Tony Blair’s chancellor when the Good Friday Agreement was signed in 1998.
His comments come after Prime Minister Andy Burnham said that a poll on Irish unity is “off the table” while visiting Belfast earlier this week.
The Prime Minister caused a political row with his comments during his first visit to Northern Ireland since coming into office.
Northern Ireland Secretary Sir Chris Bryant defended the remarks, saying Mr Burnham did not make a mistake and that he was speaking about the situation “now”, and insisted they are both “full square behind every single part of the Good Friday Agreement”.
The remarks drew an angry response from nationalist politicians on both sides of the border.
